Recently, as performances of PCs or smart devices become more advanced and devices through which a real-world image is three-dimensionally viewed such as a head mount display (HMD) are sold on the market, an interest on a three-dimensional map which simultaneously displays a color image for a space and depth information of the image is increased.
An existing two-dimensional map which is serviced by a portal has limitations in that the map can only be rotated with respect to x, y, and z axes (three degrees of freedom). However, in the three-dimensional map, not only rotation with respect to each axis, but also viewpoint movement in a three-dimensional space is allowed so that there is an advantage in that the map can be viewed while changing the viewpoint with a total of six degrees of freedom.
However, due to a limitation in a technique which generates such a three-dimensional map in an actual environment, most current three-dimensional maps are three-dimensional models which are created by a person using a three-dimensional modeling program such as a computer-aided design (CAD). Therefore, it is a common opinion in the industry that the realism of the current three-dimensional maps is less than that of the three-dimensional model using photographs taken in reality in terms of color and resolution. Alternatively, as in a road view provided by Kakao Corp., the current three-dimensional maps are limited to a form showing a 2D panorama photograph at a place where the photograph is taken.